Oct. 1, 1864.] THE TECHNOLOGIST. 



WORKING THE BATH FREESTONE. 137 



are generally from thirty to forty feet in thickness. Nowhere 

 in this neighbourhood are finer sections to be seen than at Murhill, on 

 the north side of the Bradford Valley, and Upper Westwood, on the 

 south side. The beds comprising this division usually occur, or are 

 exposed, in the escarpments of the denuded valleys or the projecting 

 downs above. Masses of the thicker and fine-grained beds frequently 

 occur on the inclined slopes of the valleya, owing to or rising from 

 frequent slips or slides over the fuller's earth upon which these lower 

 ragstones immediately rest. It is, therefore, in the narrowing of the 

 valleys and abrupt cliffs that this series of the great oolite are best 

 exposed. The chief economical value of these beds is confined to local 

 purposes, being utterly unfit for architectural work or exposure to 

 atmospheric influences. The stone used in the construction of the 

 aqueduct conveying the canal over the river Avon, at Avon Cliff, came 

 from the beds of this series at the Westwood Quarry ; and although in 

 situ the stone appears of fine texture and quality, yet it rapidly decom- 

 poses on exposure, and the stone work of the Avon Cliff aqueduct is a 

 perishing evidence of its non-durability. At the Box and Corsham 

 quarries these lower beds, though not observable at the surface, are, 

 nevertheless, forty-three feet in thickness, and are chiefly composed of 

 the fine- textured oolitic limestones, but are not worked, as they are of 

 no value in a commercial point of view. 



On the Mode oj Working the Bath Freestones. — Having endeavoured 

 to determine the horizon of the workable beds of oolite and the relations 

 they hold to the ragstones, or shelly series — recognised above and below 

 these freestones, I will endeavour to describe shortly the mode of open- 

 ing, working, and extracting the rock ; a matter of no little import- 

 ance, when we consider that more than 100,000 tons of the Bath 

 freestone is annually removed from its original position in this neigh- 

 bourhood, and forwarded to various parts of the United Kingdom. In 

 working for stone, the first question to determine is, whether the stone 

 shall be reached by open or underground workings, and this must 

 depend upon the presence and conditions of the upper ragstones (and 

 forest marble, where they exist), as they must of necessity be passed 

 through, unless the stone can be reached by tunnelling on the face of 

 an escarpment, where the beds are vertically exposed, or by driving a 

 level to cut the beds ; but if the desired beds are not too much covered, 

 open workings are resorted to. Few persons travelling from London 

 to the West of England, vid the Great Western Railway, through the 

 Box tunnel, have any conception, on passing through it, that around 

 and over them are large and extensively worked mines, from which the 

 well-known Corsham and Box freestones are taken, or as they shoot 

 from the tunnel-mouth into the Bath-hampton, Bath-eastern, and Brad- 

 ford valleys, that it is the seat of so much quarry industry, having for 

 its object the working of the Bath freestone. In describing the particular 

 mode of getting the stone, I will take for my type the Corsham 

 vol. v. R 



